KT 170

Good job, johnss.

Saved me from a future $800+ purchase.

I have a Jolida 502A tube amplifier. I have had 6550, KT 88,  KT 120, KT 150 and now the KT 170. Prior to upgrading I would speak with Jared from Jolida, CEO of Black Ice Audio and each time he told me that my amp would be able to handle the upgrades. The KT 170 is a physically larger tube, not much room between tubes. They remind of me of a 300B tube. As to the sound, there is more of everything there, except noise. I find myself not using as much volume as I used to, there is deeper and more natural bass, a wider soundstage and a little cleaner in the highs. I have had them for about 4 months and no problems with the tubes. The other tubes are 12AX7-Mullard reissues and 12AT7 Mullards. I am happy with them. Prior to buying them, I would contact the manufacture of the amp to see if the amp can handle the tubes. I hope this helps some of you.

I've had them for about 400 hours now in a primaluna evo 300 power amp. Not much increase in power (PL is a little to gentle on them, I think they might like to be driven a bit harder) but a discernable increae in control of the speakers (dhalquest dq-20's are behaving very nicely). Best way to describe them is as a GL kt-77 on steroids. Not the ones that make you grow hair, the ones that make you all sexy and stuff. Or something. Just not hairy.

It's very linear and tight with wonderful bass - very SS like in that regard but you won't mistake it for SS - at least not on my system but dayum, is it frigging nice. Very nicely extended highs and a surprisingly pleasing midrange to boot.

I really like it.  

NOS amprex in gain stage and NOS sylvania in driver stages. 

"I've had them for about 400 hours now in a primaluna evo 300 power amp."

Interesting news stickmon. According to johnss, he contacted PL and told they wont fit.

This has my buy now finger twitching.

They hit the xformers on any PL that uses 8 output tubes.

I contacted upscale audio a couple months ago about them: "We’re testing, buy kt-150’s". Screw that, you advertise as "future tube proof" so we’re gonna test. They are :)

EDIT: total cost for the 170's from viva tubes was 20 bucks less than 150's from upscale. Sure, it isn't much but thats 2 good grams of (legal) weed here.